As I posted in the comments, there should have actually been a link to this Wikipedia article on what a "color commentator" is:
A color commentator (color analyst, analyst, summariser) is a sports commentator who assists the play-by-play announcer, often by filling in any time when play is not in progress. The color analyst and main commentator will often exchange comments freely throughout the broadcast, when the play-by-play announcer is not describing the action. The color commentator provides expert analysis and background information, such as statistics, strategy and injury reports on the teams and athletes, and occasionally anecdotes or light humor. Color commentators are often former athletes or coaches of the sport being broadcast. [emphasis added]
Magically, there is an etymology section but it's not particularly helpful unless you're familiar with this use of "color".
The term color refers to levity and insight provided by a secondary announcer. A sports color commentator customarily works alongside the play-by-play broadcaster.
Here's the relevant definition of color:
- interesting and exciting details or qualities that someone or something has:
- The old market is lively, full of color and activity.
- a travel writer in search of local color
- add/give color to something (=make something more interesting)
- Intelligent use of metaphors can add color to your writing.
So, in this case, the job of the "color commentator" is to make the game more interesting by adding in small details about the rules, the players, the stadium, the fans, or any other number of subjects. Pay special attention to the bold section of the Wikipedia description above. The pieces of information in bold are the "color".